Production of ion exchange resins, the resins so produced and ion exchange processes using them

Abstract

An ion exchange resin bed capable of hydraulic segregation into discrete zones of ion exchange resins having different ion exchange functionalities, the resins being produced by functionalizing fractions of a single batch or lot of precursor copolymer which have been segregated on the basis of differing hydraulic densities of the different sized particles, and the method for producing the same.

I claim: 
     
       1. An ion exchange resin bed containing a mixture of particles bearing differing functional ion exchange groups which comprises particles prepared by functionalizing fractions of a single batch of precursor ion exchange resin copolymer particles or particles bearing an intermediate functional group or precursor thereof, segregated into said fractions on the basis of the differing hydraulic densities of the different sized particles contained in the single batch of precursor particles of substantial particle size distribution, which ion exchange particles when hydraulically classified form vertically deposed essentially discrete zones corresponding to the separately functionalized fractions wherein at least two of said zones have different ion exchange functionality. 
     
     
       2. The ion exchange resin bed of claim 1 wherein the resin bed is a stratified bed containing a weakly basic anion exchange resin as the upper zone and a strongly basic anion exchange resin as the lower zone. 
     
     
       3. The ion exchange resin bed of claim 1 wherein the resin bed is a mixed bed containing a macroreticular strongly basic anion exchange resin and a macroreticular strongly acidic cation exchange resin. 
     
     
       4. The ion exchange resin bed of claim 1 wherein the resin bed consists of particles having a styrene and divinyl benzene backbone copolymer. 
     
     
       5. The ion exchange resin bed of claim 1 wherein the resin bed consists of particles having a crosslinked acrylic backbone. 
     
     
       6. A method for deionizing a fluid medium which comprises passing said fluid through an ion exchange resin bed in accordance with claim 1. 
     
     
       7. A process for manufacturing an ion exchange resin bed capable of hydraulic classification into essentially discrete zones of ion exchange functionality which comprises separately functionalizing fractions of a single batch of precursor ion exchange resin copolymer particles or particles bearing an intermediate functional group of precursor thereof, segregated into said fractions on the basis of the differing hydraulic densities of the different sized particles contained in the single batch of precursor particles of substantial particle size distribution, which ion exchange particles when hydraulically classified form vertically deposed essentially discrete zones corresponding to the separately functionalized fractions wherein at least two of said zones have different ion exchange functionality. 
     
     
       8. The process of claim 7 wherein the ion exchange copolymer beads are physically separated before functionalization by screening. 
     
     
       9. The process of claim 7 wherein the ion exchange copolymer beads are physically separated before functionalization by hydraulic classification.